The invention relates more particularly to a motor vehicle drum brake including:                a fixed transversal plate;        a drum rotatably mounted with respect to the plate and equipped with a peripheral friction skirt;        two opposite braking segments including first transversally facing ends and second transversally facing opposite ends;        an anchoring element inserted transversally between the second ends of the braking segments such that each second end is elastically forced to pivotably transversally bear against an associated bearing surface of the anchoring element;        a wheel cylinder which, in a first so-called “simplex” operating mode of the drum brake, is suitable for transversally separating the two adjacent first ends of the braking segments, pivoting the braking segments about the fixed bearing surface thereof with respect to the plate, to apply a friction surface of each braking segment against the friction skirt.        
Drum brakes of this type, also called “floating segment drum brakes” as the segments bear on the anchoring element without being attached thereto are already known. This enables automatic centring of the segments when they are applied against the peripheral friction skirt of the drum.
The drum brakes are conventionally used alternatively as a service brake, and as a parking brake.
During use as a service brake, the drum brake makes it possible to slow down or even immobilise the vehicle. During this use, the driver controls the intensity of the braking torque applied by the drum brake by means of a first control member such as a brake pedal.
During use as a parking brake, the drum is used to immobilise the stationed vehicle. The drum brake is then controlled in “on/off” mode so as to apply a powerful braking torque to the vehicle wheel. During this use, the driver generally controls the drum brake by means of a second control member, for example by means of a hand brake pulling a brake cable.
This type of brake is satisfactory for service brake use as it makes it possible to distribute wear over the entire surface of the friction linings. Nevertheless, it has been observed that the braking torque could be insufficient for use as a parking brake.